The thermal behaviour of γ-CaSO4

被引：19

作者：

Ballirano, Paolo ^{[1
]}

Melis, Elisa ^{[1
]}

机构：

[1] Univ Roma La Sapienza, Dipartimento Sci Terra, I-00185 Rome, Italy

来源：

PHYSICS AND CHEMISTRY OF MINERALS | 2009年 / 36卷 / 06期

关键词：

Soluble anhydrite; gamma-Anhydrite; gamma-CaSO4; Thermal behaviour; X-ray powder diffraction; Rietveld method; CALCIUM-SULFATE HEMIHYDRATE; X-RAY-DIFFRACTION; RIETVELD REFINEMENT; GYPSUM DEHYDRATION; TEMPERATURE-RANGE; CRYSTAL-STRUCTURE; ANHYDRITE CASO4; PHASE; TRANSFORMATION; BASSANITE;

D O I：

10.1007/s00269-008-0280-0

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Thermal behaviour of gamma-anhydrite (gamma-CaSO4, soluble anhydrite) has been investigated in situ real-time using laboratory parallel-beam X-ray powder diffraction data. Thermal expansion has been analysed from 303 to 569 K with temperature steps of 4 K. Lattice parameters and volume were fitted with a second-order polynomial to calculate thermal expansion coefficients. Thermal expansion of gamma-anhydrite is anisotropic being larger along the c axis. Within the 343-383 K thermal range, gamma-anhydrite has been found to partially re-hydrate to bassanite CaSO4 center dot 0.5H(2)O. At 455 K the transformation gamma-CaSO4 -> beta-CaSO4, insoluble anhydrite, starts reaching completion at 653 K.

引用

页码：319 / 327

页数：9

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